EP 1071855 discloses a toilet pan body including a double acting air pump for both pressurizing a toilet cistern for forcing water into a toilet pan and for providing air into the toilet pan for flushing purposes. The toilet pan body has as hinged lid which can be sealed on top of the toilet bowl so that a chamber can be formed below a seal/locking assembly and the pan bowl below it, the seal/locking assembly having a compression seal for making an air tight seal with the rim of the pan when the toilet lid is closed, so that air pressure provided inside the chamber will cause the contents of the pan to be evacuated. The seat and lid of the toilet have separate brackets which are connected to chassis outriggers. Due to the close tolerances required for the sealing with the compression seal, the toilet pan bowl and sealing/locking assembly and toilet lid can only be made of a material such as metal which can be reliably made to very close tolerances in size during manufacture. Furthermore, the compression seal is not particularly effective at adjusting to accommodate movement of the lid away from the pan during pressurization. Also, a latch for holding the toilet lid closed is relatively complicated and involves engagement of a latch bolt with the interior surface of the toilet pan which is not particularly hygienic. Additionally, the toilet lid and toilet seat cannot easily be removed from the toilet pan for cleaning and repair purposes. Furthermore, the air pump requires a significant amount of room behind the toilet pan and toilet pan has to have separate entry points for the air and water into it.
In EP-A-1838193, it is noted that sealing arrangements for sealing a lid to a body require a high level of manufacturing accuracy which is aggravated by the fact that sanitary ware is most conveniently produced in ceramic material, where a high level of dimensional accuracy is not possible due to distortion encountered in the manufacturing process. This document discloses a toilet having a seat and lid. The seat may be sealed to a rim area of the toilet pan by a peripheral seal and the lid may be sealed to the seat by a similar seal. However, it has been found that a high level of skill and attention is required during assembly otherwise the seals used are not always consistent around the full periphery thereof and a flexible flange of each of them which extends downwardly and inwardly from the lid or seat to which it is secured can have an uneven configuration along the length periphery thereof. The toilet also includes a handle member extending all of the way around the curved front edge of the toilet, the handle member being arranged to act upon two latches positioned on the two sides of the toilet lid and which have hooks arranged to releasably engage in respect recesses in the sides of the ceramic toilet pan. It is necessary to have two such hook members on the sides of the pan so that the hooks and recesses will still engage one another despite variation of the sizes of the ceramic pans which will be produced in each batch, due to varying sizes of the pans occurring naturally during the firing process of the ceramic pans and also due to slight changes in the pan molds each time the molds are used, the molds typically being plaster and varying in size each time they are used. The latch arrangements so formed are relatively expensive to make and the toilet parts cannot easily be disassembled for cleaning/repair purposes. Furthermore, pressure on the handle member for example by sitting on it when it is slightly raised may cause a trapping hazard.
Further, EP-A-1838193 goes on to show a toilet pan constructed with a lid and seat hinge axis located horizontally through vertical opposing faces positioned within indents provided in the side of the pan. This method of construction has the advantage that the components of the hinge attachment method are elevated away from the horizontal surface of the pan top where the hinges of traditionally WCs are positioned and which makes them susceptible to contamination with urine during use, whereupon they require regular cleaning, are prone to the ingress of urine and cleaning chemicals into the hinge pin and screw clamp components whereby lubrication, swelling and corrosion of the fixings occurs resulting in torsional/skew movement of the lid and seat in relation to the pan during subsequent normal use, and an unpleasant odor developing over time, which all require disassembly to rectify, where removal of the lid and seat may be impaired by the corroded hinge fixing components. However, known methods of providing a horizontal hinge located in vertical opposing faces in the side of the pan require the hinge components to be mechanically fixed into or clamped onto holes on faces that may not be perfectly parallel due to the fact that the faces may be required to have draft angle to allow de-molding during the ceramic pan manufacturing process. Poor surface finish and/or distortion during manufacture may further cause the side faces to diverge from parallel. These inaccuracies cause co-axial misalignment of the left hand and right hand hinge pins.
Furthermore, due to the way ceramic toilet pans vary in size during the firing process, it is usual to provide two relatively large vertical bores on either side of the ceramic toilet pan at a rear end thereof through which narrower hinge components for the toilet seat and lid may be inserted relatively loosely, before adjustment in the forward/backward and left/right directions and before clamping of the hinge parts in place by tightening clamps. However, the clamps/hinge parts can loosen over time allowing the toilet lid and seat to move undesirably relative to the ceramic pan.
Furthermore, many known toilet cisterns do not have very effective overflow arrangements for preventing the cisterns from filling up too much in the event of their water inlet jamming open or, in the case of toilets with a closeable lid, from preventing foul water backflowing into the cistern from the WC in the event of sewer malfunction or flood, whereupon it is desirable for the water inlet to remain uncontaminated to protect potable water supplies.
Those cisterns that are known to provide protection against such fluid category 5 contamination are provided with a non circular overflow weir to free space through the side of one of their wall of construction, but this is unsightly and makes collecting the overflow water for onward drainage difficult and space consuming.
Furthermore, with reduced flush volumes, it is necessary to accurately direct the flow of water into the pan in order to wash its surface effectively. Water distribution nozzles are an effective way of washing the pan with little water, and the consequential elimination of a flushing rim aids cleaning and hygiene. However, the construction of modern ceramic toilets can require double wall sections, which leave limited access to locate and attach the nozzle assemblies. Ceramic sanitaryware may also have a range of wall thicknesses produced throughout the life of the mold, with nozzle holes often cut by hand causing deformation and back-surface irregularities, which make attaching and sealing nozzle assemblies difficult.
The present invention aims to alleviate at least to a certain extent at least one of the problems of the prior art.